Heat engine cycle.

In the heat engine cycle

a. work output is greater than heat input
b. work output is less than heat input
c. work output is equal to heat input
d. none of the above

Correct Answer : b. work output is less than heat input

Explanation :

Heat engine utilizes the heat energy coming from the source and produces work output. But all the heat energy from the source is not converted into work and some amount of heat energy is rejected to the thermal energy reservoir which is called as sink. Therefore complete conversion of heat energy into work output is not possible. Therefore, work output is less than heat input.